Knock-down interlocking carton closure



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KNOCKDOWN INTERLOCKING CARTON CLOSURE Filed May 31, 1935 INVENTOR, flri'z urcl "@655,

I D. ATTORIYQEY.

Patented Sept. 8, 1936 PATENT OFFICE aosaasv KNOCK-DOWN INTERLOCKING csnron CLOSURE Arthur J. Weiss, Englewood, N. 3., assignor to Robert Gair Company, Inc., New York, N. Y., a corporation of Delaware Application my 31, 1935, Serial No. 24,441

11 Claims.

The present invention relates to cartons made of paper board and has for its principal features the construction of a machine made carton cut into a blank and joined by a lap, by gluing, or

5 stapling, into a fiat knock-down carton blank. As thus made it is shipped to the user in bundles, and the user erects the blank into carton assembly bya quick manual manipulation.

A further feature in the present construction is in the provision of an interlocking carton closure, whereby by over-folding the carton closure forming flaps" in a certain orderly and sequential manner and then pressing the flaps inwardly, the tongues, edges, tabs and extensions upon the edges and surfaces of the flaps spring into interlocking engagement, in such a manner as to prevent the interlocked flaps, if they are used as a bottom closure, from outward collapsing under the contained load within the 20 carton.

The foregoing, and other features of advantage will be apprehended as the herein description proceeds andit is obvious that modifications may be made in the structure herein, without depart- 25 ing from the spirit hereof or the scope of the appended claims.

In the drawing,

Fig. 1 is a, perspective view of the carton in the act of engaging the closing flaps; v

Fig. 2 is a similar view, showing a further step in closure;

Fig. 3 is a further step in closing the carton;

Fig. 4 shows the flaps interlocked in final closure;

Fig. 5 shows a stretchout of the blank;

Fig. 6 shows the carton in fiat assembly;

Fig. '7 is an enlarged, fragmentary, sectional view taken on line I-'I, Fig. 4, looking in the direction of the arrows; and I Fig. 8 is an enlarged, fragmentary, sectional view taken on the line 8-8, Fig. 4,1ooking in the direction of the arrows.

As shown in Fig. 5, the blank, preferably made up of fibre board, comprises body forming panels, or side walls, I, 2, 3 and 4. Panel 4 carries a staple or glue lap 5. The panels and lap are defined from each other by folding, or score lines A, B, C and D, shown dotted.

Each panel carries a closure flap at one side thereof, the flaps being I, 8, 9 and Ill, and these are defined from the panels I to 4 inclusive, by a common score line H, panel I being provided with closure flap I, panel 2 being provided with closure fiap 8, panel 3 being provided with closure flap 9, and panel 4 being provided with closure flap I0.

Flaps I and 9 are provided with lock tabs ab and -11 respectively, these being located on the opposite sides of said flaps and at the outer extremities thereof. In the folded assembly as in Fig. 6, these fiaps I and 9 are opposed to each other.

Flap I is provided with an indent e on its outer edge and flap 9 is provided with an interfitting extension I, which, when the flaps are interlocked, as in Fig. 4, underlies flap I and engages into in- 10 dent e, thus to prevent theclosure flaps from opening outwardly under loads within the carton and forming an outer closure lock for all the interlocking flaps. In effect, the lock tabs (It-b and 0-11 are like modified so-called Hibson looks.

The flaps 8 and III are each provided with re: silient, or springing, cut-out tabs 9 and hat their midsections and are so located that when the closing flaps are all infolded, as in Figs. 3 and 4, I lock tabs a and d conjointly register with spring tab h, while lock tabs b and a register 'conjointly with spring tab g. Spring tabs g and h are formed by cutting clean through the flaps 8 and I0, thus leaving two cut sides 2'--i joined by a curved cut 7. The purpose of these curved cuts 7' is to permit the modified Hibson locks to easily enter under the spring flaps g and h,.when all of the flaps are bent inwardly under lock engaging pressure, as, when so bent, all of the flaps are sprung inwardly and downwardly a considerable distance to enable them to automatically interengage. The curved cuts i therefore partake of the conjoint angularity of the bent in flap locks ab and 0-11 and favor the easy entry of the locks into the cuts 7' and under the flaps g and h.

The panels I to II inclusive on their sides opposite the closure flaps I to III inclusive are provided with narrow in-foldable wall stiffening flaps 6-4-6 and 6, scored from the panel assembly by a common score line E, shown dotted. 40 This end of the carton may be closed by a removable lid, not shown.

In the assembly of the carton, the blank of Fig. 5 is over folded first on score line C, thus overlaying panel 4 and its lap 5 on panel 3. Then panel I is overfolded on score line A, so that panel. I overlays panel 2, and the end G of panel I overlays Ian 5, and the end G and lap 5 are then secured together, as by staples :c, Fig. 6, with lap 5 underneath edge G of panel I.

when the carton is erected for use, the fiat assembly, Fig. 6, is manually opened to rectangular form, as in Fig. 1, and flaps 8 and III are first infolded on common score line H. These flaps 8 and I0 may be of such a'length that when in- Q folded and in looking position their outer edges m and 12 may overlap slightly, thus to form a stiffening overlap lock between themselves as at m and n, Fig. 7. This lap lock is reinforced by the locking of the other elements, to be described, so that the line of overlap mn forms a central line of stiifening which is transverse to the lock flaps I and 9, as also in Fig. 8.

The flaps I and 9 are then infolded, over flaps 8 and ID, as in Figs. 2 and 3, and as in Fig. 3, all four fiaps are pushed down, until a. and c and b and (1 enter into the curved cuts i7' of spring tabs 9 and h, and simultaneously causing extension tab ,f to enter into indent e and under fiap I. When this interlock pressure is removed, all four flaps 1 to spring upwardly in interlocked engagement, as in Figs. 4 and 7.

The actual closing and interlocking engagement of flaps I to ID consume only a few secends, and creates a firmly locked closure, resistant against outward collapse against an inner load thereon.

Having thus described the invention what is claimed is:

1. A carton comprising four body forming panels including two terminals, a fastening lap on one of said terminal panels, said body panels and lap being scored from each other by parallel scoring, said lap being attached to connect its panel to another terminal panel to form a carton, closure forming interlocking flaps scoredly attached by a common score line, one flap to each panel, two of said flaps, as opposed, forming under flaps, having resilient locking means at their mid-portions, said means including spring tabs and there being openings thereat, and a second pair of opposed locking closure flaps, forming outer closing fiaps and alternately located relative to said first two closure flaps, said second pair of opposed locking flaps being provided with locking means on their edges, said second means including locking tabs and being located, when infolded, over the first said two flaps, to coact to lockably engage with the spring tabs of said first two flaps when all of the fiaps are sprung inwardly below the normal closing plane of all of said flaps, said locking tabs being engageable in edge to edge relation in the openings, so as to cause automatic, simultaneous interengagement of all of said locking means.

2. A blank for a knockdown carton comprising four alined body forming panels, two panels being terminal panels, all of said panels being defined from their adjacent panels by scoring, narrow stifiening flaps on one edge of each panel and defined therefrom by a common score line, a closing flap on the opposite edges of each panel, said closing flaps being scored from said panels by a common score line, one of said terminal panels having an attaching lap thereon, the fiap on said terminal panel having a resilient cut-out tab located at its mid-portion, the next adjacent fiap having lock tabs on its side edges at the outer extremity thereof, the outer edge thereof having an interfitting extension thereon, the next adjacent flap having a resilient cut-out tab located at its mid-portion, the next and last adjacent and terminal panel having its flap arranged with lock tabs on its side edges at the outer extremity thereof and a locking indent on its outer edge. I

3. A blank for a knockdown carton comprising four alined body forming panels, two panels being terminal panels, all of said panels being defined from their adjacent panels by parallel scoring, narrow stiffening flaps on one edge of each panel and defined therefrom by a common score line, a closing flap on the opposite edge of each of the body forming panels, said closing fiaps being scored from said panels by a common score line, one of said terminal panels having an attaching lap thereon, the flaps on said two alternate panels having resilient cut-out tabs located at their mid-portions, the other two alternate pair of flaps having lock tabs on their side edges at the outer extremities thereof, and having interfitting locking means on the outer edges thereof.

4. A carton comprising four body forming panels including two terminal panels, a fastening lap on one of said terminal panels, said body panels and lap being scored from each other in parallel lines, said lap being attached to connect its panel to another terminal panel to form a carton, closure forming interlocking flaps scoredly attached to said body panels by a common score line, one flap to each panel, two of said fiaps, forming outer closures, as opposed, having lock tabs on opposite side edges near the extremities thereof, one of said flaps having a locking indent on its outer edge the other said flap having an extension on its outer edge to coact with said indent when in locked position, and a second inner pair of opposed locking closure flaps alternately located with said first two closure flaps said second pair of opposed looking flaps being provided with resilient cut-out tabs located at their mid-sections and located, when infolded, to coact to lockably engage with the lock tabs of said first two flaps when the latter are sprung downwardly below the normal closing plane of said flaps to cause automatic, simultaneous interengagement of all of said locks.

.5. A carton formed from a blank of relatively stiff paper board comprising two pairs of opposed sides and a closure including two under flaps and two outer flaps, there being one flap on each side; said under flaps having therein opposed medial cuts and being folded into horizontal closing position, said cuts having sub-cuts extending inwardly from their ends, said outer flaps being also folded into substantially horizontal position and having meeting marginal edges above the under flaps, and short lock tabs extending from the sides of said outer flaps at said edges, said tabs having their ends slightly overlapping the outer boundaries of said cuts, so that the flaps may be pressed inwardly past said position to snap said ends into the cuts, whereby when the pressure is released the flaps may spring back to said position, to lockingly hold said ends below said boundaries.

6. A carton formed from one sheet 01. fibre board comprising four sides and a closure including four substantially horizontally disposed flaps, two of said flaps forming under members and having therein opposed cuts which provide openings, there being angular sub-cuts at the terminals of the cuts, the other two flaps being outer members and having meeting margins between the cuts, one of said margins having therein a recess, and there being an extension on the other margin, said extension having its end lockingly engaged below a boundary edge of the recess; said margins having side tabs extending therefrom and the ends of said tabs being lockingly engaged below the outer boundaries of said cuts, whereby when the closure is pressed inwardly past said amass? spective locking boundaries so that the closure may be opened.

7. A carton formed from a blank of relatively stiif card board comprising two pairs of opposed side walls and a closure including two under flaps and two outer flaps, there being fold lines between said walls and the flaps; said under flaps having therein opposed medial cuts which provide openings, there being angular sub-cuts at the ends of the cuts and the under flaps being folded into a substantially horizontal closing position, the side margins of said under flaps being disposed against the interposed opposite side walls at the central line of the outer flaps; said outer flaps being also folded into horizontal position and having edgemeeting end margins between said openings, and means for holding the outer flaps in said position, said means including the under flaps, there being short lock tabs extended from opposite sides of the last mentioned margins, whereby both pairs of the flaps may be pressed inwardly past said position to cause said tabs to lockingly enter the openings while said end margins remain substansure flap extending from each wall, comprising two lock tabs which extend from opposite sides of one member of said flaps at the end edge thereof,

two other members 01' said flaps being opposite and lowermost in the closed position, said lowermost members having therein opposed cuts and extending from each wall, twoot said flaps being outer members and two flaps being under members, said outer members being extended half diametrally across the carton in the closed position and having relatively narrow ends, said under members having therein arcuate cuts opposite the sides of said ends, said cuts having at their opposite terminals angular sub-cuts to provide tabreceiving openings, and pairs of short lock tabs extending from said sides at said ends and being engaged in the openings, said tabs having their side edges formed to substantially correspond with the contour of the cuts, so that the flaps may be pressed inwardly past the normal closed position, whereby said tabs may then be disengaged to open the closure.

10. A carton formed from a blank or relatively stiff paperboard which is scored to provide co- -members and their associated side walls; one of the other two 'fiaps being an outer member and having its end margin disposed between said cuts, said margin having thereon short side tabs which are disposed in the openings, the ends of said tabs being lockingly engaged under the outer boundaries of the cuts, whereby the closuremaybe pressed inwardly past the horizontal position so that said tabs may be released for opening the closure.

1'1. A carton comprising a sheet of paperboard which is cut and scored to form four permanently interconnectible side walls each having a closure flap foldably associated therewith, two of said flaps being under members and being folded into substantial horizontal position, said members being extended practically hali' diametrally across the carton and having therein opposed arcuate cuts which form openings, said cuts being distant from the supporting walls of saidmembers,

and there being angular sub-cuts extending inwardly from the opposite end of said cuts; the other two flaps being outer members and having their end margins disposed between said cuts in the folded position, said outer members having their side edges inclined inwardly so as to register at their inner ends with the ends of the arcuate cuts, and there-being short tabs extending from the ends of said margins, the tabs of the associated ends forming pairs and the distance across each pair of the tabs being equal to the length 01 the cuts, said tabs having their side edges formed 

